package day28_35.day33;

import java.util.Scanner;

public class Main02 {
    public static void main(String[] args) {
        Scanner scn = new Scanner(System.in);
        long[] arr = new long[90];
        arr[0] = 1; arr[1] =1;
        for (int i = 2; i < arr.length; i++) {
            arr[i] = arr[i - 1] + arr[i - 2];
        }
        int num = 0;
        while (scn.hasNext()){
            int from = scn.nextInt();
            int to = scn.nextInt();
            for (int i = from; i <= to ; i++) {
                num += arr[i - 1];
            }
            System.out.println(num);
            num = 0;
        }
    }
}
